The present invention relates to controlled release of various substances into fluid environments generally, and more particularly to a device providing a controlled release of various substances including microorganisms into aqueous environments. This invention also relates to methods for controllably releasing various substances from a contained source.
A number of applications exist today in which various materials are desired to be dispensed into fluid environments, particularly into aqueous environments. Further, many such applications seek a controlled release function to slowly release such materials over a desired period of time. Such applications include, for example, chemical additions to drinking water, swimming pools, water fountains, and waste water treatment facilities, preservation materials into fluid supply stocks, and additives to various food and beverage preparation mixes. A variety of other applications for releasing materials into desired fluids exist today.
One problem that exists in implementing such applications is the difficulty in controllably dispensing such materials at a desired rate. Many instances arise in which a slow, controlled release is preferable over an instantaneous xe2x80x9cchargexe2x80x9d to the fluid. As a particular example of a situation where controlled release is desirable is the release of microorganisms into contaminated water, as described in U.S. Pat. No. 5,879,932, assigned to the assignee in the present application. Thus, a reliable technique for controllably releasing various substances into surrounding fluid environments in a variety of fluid flow conditions is desired.
Accordingly, it is a principle object of the present invention to provide a device for controllably releasing substances into fluid environments.
It is a further object of the present invention to provide a device for controllably releasing substances into flowing fluid environments.
It is a still further object of the present invention to provide a biodegradable device for controllably releasing substances into fluid environments.
It is a still further object of the present invention to provide a device for controllably releasing microorganisms into aqueous fluid environments.
It is a yet further object of the present invention to provide a device for culturing and controllably releasing microorganisms into fluid environments.
It is another object of the present invention to controllably release substances into fluid environments at a rate of no more than 0.5 g/day/cm2.
It is a still further object of the present invention to provide a means for floating a controlled release device near the top surface of the fluid receiving the dispensed substances.
It is a yet further object of the present invention to provide a means for sinking a controlled release device to the bottom of the fluid receiving the released substances.
By means of the present invention, substances may be controllably released into surrounding fluid environments at a rate of no more than 0.5 g/day/cm2 through the utilization S of a porous container. Such controlled release is achieved by placing the substances to be released within the porous container and subsequently placing the charged container into the desired fluid.
One embodiment of the present invention provides for a sealed pouch comprising porous material having pores sized and configured to allow the substances contained within the pouch to pass through the pores at a rate of no more than about 0.5 g/day/cm2. The sealed pouch may be biodegradable, and is preferably fabricated from a fibrous paper material.
Another preferred embodiment of the present invention includes a porous container for controllably releasing microorganisms contained therein into fluid environments. In such an embodiment, the porous container preferably initially contains a mixture of microorganisms, nutrients, and a suspending fluid. As in other embodiments, the porous container may be biodegradable, and is preferably fabricated from a fibrous paper material.
Another embodiment of the present invention includes a dispensing vessel and a porous container disposed within the dispensing vessel, wherein the porous container comprises porous material having pores which are sized and configured to allow substances to pass through the pores at a controlled rate. Preferably, at least a portion of the dispensing vessel includes open channels extending through an exterior of the vessel, such that fluids surrounding the dispensing vessel may be in contact with the porous container disposed therein. In particularly preferred embodiments, the dispensing vessel includes a floating portion and a growth chamber that is removably secured to the floating portion, with the growth chamber depending downwardly therefrom. The hollow chamber defined within the growth chamber is preferably open to the surrounding fluid such that the porous container being disposed in the hollow chamber may be in fluid communication with the fluid surrounding the growth chamber.
The present invention also contemplates a method for culturing and controllably releasing microorganisms into fluid environments. The method includes providing a porous container having microorganisms, nutrients, and a suspension fluid disposed therein, with the porous container comprising material having pores which are sized and configured to allow the microorganisms to pass through the pores at a rate of no more than about 0.5 g/day/cm2. The porous container is then placed into an aqueous environment, thereby allowing the microorganisms to culture within the container and to controllably release into the aqueous environment.